The present invention relates to the field of turbine insulation, and more specifically, to insulation systems for the exteriors of turbines and associated piping and fittings, and methods for insulating the same.
During the past decade, the gas turbine has emerged as the world""s dominant technology for electricity generation. Power companies have built large numbers of new power plants using gas turbines, as a result of their relatively low capital cost, relatively high thermal efficiency and relatively low environmental impact.
Turbines, and associated piping and fittings, are typically provided with an exterior layer of insulation. This improves operating efficiency. As well, it reduces ambient temperatures in the vicinity of the turbine, so as to permit personnel to work in relatively close proximity to the turbine, which would not otherwise be practical.
The insulation provided for said piping and fittings is often mineral material, such as rock wool, which is wrapped in a sealing layer of fiberglass. This provides adequate insulation value. However, as it is necessary, from time to time, to inspect piping and fittings, which requires the time-consuming removal and replacement of said insulation, this manner of insulation can suffer from poor economies.
For turbines, it is known to employ removable insulation blankets. Such blankets are usually custom-shaped, to circumvent piping and the like, which typically bristles from the exterior of a turbine, and are secured by impalement on spikes which are spot-welded to the turbine housing and capped with self-locking washers.
To improve seal integrity between adjacent blankets, lacing hooks are provided on the blankets, and the assembly is tightly laced together with stainless steel soft gauge wire.
This manner of insulation can suffer from poor aesthetics, which can be of significant concern when the capital cost of a turbine is considered. Moreover, proper installation, to obtain acceptable levels of aesthetics and thermal insulation, is relatively time-consuming, even with skilled labour. This can be problematic, as it is necessary to periodically remove the insulation for inspection and maintenance of the turbine, and turbine down-time costs an average utility in lost revenue approximately $1 million per day. It is not unknown, for example, for the removal and installation of a conventional blanket system to take three working days, with commensurate impacts on the bottom line.
It is an object of the present invention to provide an insulation system for use with a turbine housing of the type having a tubular exterior surface centered about and defining a horizontal longitudinal axis, a vertical joint raised relative to the tubular exterior surface and dividing the housing into fore and aft tubular portions and a pair of horizontal joints raised relative to the tubular exterior surface and dividing the housing into upper and lower arcuate portions, said insulation system providing an adequate insulation value, being relatively aesthetically pleasing and economical to manufacture and being relatively convenient to install and remove, as compared to insulation systems of the prior art.
This object, and others, is met by one aspect of the present invention, an insulation system for use with a turbine housing of the type having a tubular exterior surface centred about and defining a horizontal longitudinal axis, a vertical joint raised relative to the tubular exterior surface and dividing the housing into fore and aft tubular portions and a pair of horizontal joints raised relative to the tubular exterior surface and dividing the housing into upper and lower arcuate portions.
The insulation system comprises four insulation blankets, a pair of first insulation ribs for each longitudinal channel, a pair of second insulation ribs, and an insulation coupling member for each longitudinal channel.
The four insulation blankets are removably positioned, in use, at respective operative positions upon said tubular exterior surface, in spaced relation to the horizontal joints and to the vertical joint so as to define between one another, in combination with the tubular exterior surface of the housing, an annular channel in which the vertical joint is positioned and a pair of longitudinal channels each intersecting the annular channel and having positioned therein a respective horizontal joint.
The pair of first insulation ribs for each longitudinal channel are removably positioned, in use, respectively, fore and aft of said vertical joint, in volume-filling relation to said each longitudinal channel, in straddling, close-fitting relation to the horizontal joint positioned in said each longitudinal channel and in overlapping relation to the insulation blankets disposed, respectively, on the fore and aft tubular portions of the housing.
The pair of second insulation ribs are removably positioned, in use, respectively, above and beneath the horizontal joints, in volume-filling relation to the annular channel, in straddling, close-fitting relation to the vertical joint, and in overlapping relation to the insulation blankets disposed, respectively, on the upper and lower arcuate portions of the housing.
The insulation coupling member for each longitudinal channel is removably positioned, in use, in said each longitudinal channel at the intersection thereof with the annular channel, in volume-filling relation to a void defined by the housing, the first insulation ribs and the second insulation ribs, in straddling, close-fitting relation to the horizontal joint positioned in said each longitudinal channel and to the vertical joint, and in lapped relation to the first insulation ribs and the second insulation ribs.
Another aspect of the invention is a method for insulating a turbine housing of the type having a tubular exterior surface centred about and defining a horizontal longitudinal axis, a vertical joint raised relative to the tubular exterior surface and dividing the housing into fore and aft tubular portions and a pair of horizontal joints raised relative to the tubular exterior surface and dividing the housing into upper and lower arcuate portions.
As steps of the method, the insulation system of the invention is provided, and the insulation blankets thereof are removably positioned at their respective operative positions upon said tubular exterior surface in spaced relation to the horizontal joints and to the vertical joint so as to define between one another, in combination with the tubular exterior surface of the housing, an annular channel in which the vertical joint is positioned and a pair of longitudinal channels each intersecting the annular channel and having positioned therein a respective horizontal joint.
As another step of the method, with respect to each longitudinal channel, the pair of first insulation ribs therefor are removably positioned, respectively, fore and aft of said vertical joint, in volume-filling relation to said each longitudinal channel, in straddling, close-fitting relation to the horizontal joint positioned in said each longitudinal channel and in overlapping relation to the insulation blankets disposed, respectively, on the fore and aft tubular portions of the housing.
As another step of the method, the pair of second insulation ribs are removably positioned, respectively, above and beneath the horizontal joints, in volume-filling relation within the annular channel, in straddling, close-fitting relation to the vertical joint, and in overlapping relation to the insulation blankets disposed, respectively, on the upper and lower arcuate portions of the housing.
As a further step of the method, the pair of insulation coupling members, are removably positioned, respectively, in each longitudinal channel, at the intersection thereof with the annular channel, in volume-filling relation to a void defined by the housing, the first insulation ribs and the second insulation ribs, in straddling, close-fitting relation to the horizontal joint positioned in said each longitudinal channel and to the vertical joint, and in lapped relation to the first insulation ribs and the second insulation ribs.
Other advantages, features and characteristics of the present invention will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter of which is briefly described hereinbelow.